At present, wireless communication is used so widely and many products or merchandise are set to be wirelessly communicable. For example, a wireless mouse can be used for a notebook-type personal computer. A wireless remote controller is used for many toys for kids. A wireless earphone is used for a wireless player. Further, at present everyone owns and daily uses a mobile phone.
The wirelessly communicable products as described above cannot send a signal in the frequency band (airband: 108 MHz to 137 MHz) used in the aviation industry. However, the products may send a spurious signal (unwanted signal) in a frequency band belonging to the airband.
However, a user cannot determine whether the products may send a spurious signal. Thus, a person who is taking a trip can hardly expect that a wireless communication device which he/she brings to an airport causes communication devices (such as navigational equipment of an aircraft) making indispensable communication for the aviation industry to erroneously operate, consequently endangering a fright of the aircraft.
Additionally, the above situation has not actually occurred so far, and thus a method or a system for avoiding such a situation has not been proposed at all (no prior art document information). Thus, cabin attendants and the like of an aircraft only ask passengers to turn off the power supplies of wireless communication devices before leaving. However, the passengers may forget or fail to turn off the power supplies of the wireless communication devices due to the hustling during travel.
Therefore, it is required to specify a wireless communication device sending a signal which can deteriorate safety in the aviation industry.